4 ms·
Infrared is the only way to see things that are cold (as in not a star) or extremely far away (due to redshift).
by foobarbecue 4y ago
Infrared is the only way to see things that are cold (as in not a star) or extremely far away (due to redshift).
- skybrian 4y agoWhat about reflected light, like most things we see in the solar system?
- foobarbecue 4y agoGood point, I shouldn't have said "only." I have heard of reflected light been used for exoplanet observations although I think it's quite faint. I guess some nebulae are illuminated by stars. I don't know if the reflected light is longer wavelength than the incident light, but I suspect so. BTW I'm not an astronomer!